Image protection

Abstract

A method (100) of marking an image comprising image data and associated metadata, for modification detection, is disclosed. The method (100) encodes the image data to produce encoded image data and hashes the encoded image data to provide a first hash. The first hash is added to the associated metadata to form augmented metadata the associated metadata is hashed to provide a second hash. The second hash is added to the augmented metadata. An association is created between the encoded image data, the first and second hash, and the augmented metadata, thereby marking the image.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates generally to digital imaging and, in particular, to embedding supplementary information in a digital image and to the authentication of the embedded supplementary information. The invention also relates to a computer program product including a computer readable medium having recorded thereon a computer program for embedding supplementary information in a digital image and authenticating the embedded supplementary information.BACKGROUND ART[0002]The need for image protection has been increasing in recent years and as a result at least two forms of image metadata have been growing in importance. These forms of image metadata are firstly, authentication information, which is used to determine whether an image has been altered since acquisition, and secondly, intellectual property rights information (e.g. copyright labelling), which is used to identify the party or parties having intellectual property rights in the ima...

AI Technical Summary

Benefits of technology

[0007]It is an object of the present invention to substantially overcome, or at least ameliorate, one or more disadvantages of existing arrangements.

Problems solved by technology

Conventional techniques for associating these forms of image metadata often have conflicting requirements, which presents several problems when both of these forms of image metadata are to be included in a single image.

Interference between different watermarks and / or added degradation of image quality can occur when different types of watermarks are used together.

Therefore, it is generally undesirable to use more than one type of watermark within a single image.

The SDMI technique is however undesirable when used just for the purpose of authentication.

In particular, the use of fragile watermarks can result in modifications to an image that may impact on the compressibility and / or the visual quality of the image.

Also, since fragile watermarks are by their very nature fragile, these watermarks can be lost completely if the image is modified making it difficult to provide additional information to a user about the type or extent of modification.

However, copyright information embedded, as metadata in a file wrapper is potentially open to malicious modification or malicious or accidental removal during processes such as file format conversion.

In addition, copyright information embedded using watermarks is not easily visible to applications software and there is no way of guaranteeing that the watermark was not inserted fraudulently, say after stripping of copyright metadata tags.

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